DEVELOPMENT OF A NUTRITIONAL STRATEGY FOR INCREASING LAMB SURVIVAL INMERINO EWES MATED IN LATE SPRING EARLY SUMMER

A nutritional strategy for increasing lamb survival in Merino ewes mat ed in late spring/early summer was evaluated in a commercial flock ove r two consecutive years (Year 1, n = 680; Year 2, n = 325). The strate gy combined the 'ram effect' to synchronise oestrus and hence parturit ion, plus supplementary feeding of lupin grain for 14 days in the expe cted early post-parturient period. Supplementary lupin feeding commenc ed 12 days after the expected start of lambing. Lambing was highly syn chronised over a 14-day period commencing 17-19 days after the expecte d start of lambing, in both years. Supplementary feeding did not affec t lamb birthweight in either year but subsequent increases in weight w ere observed at weaning in Year 1 (1.4 kg; P = 0.06) and tail docking in Year 2 (1.3 kg; P < 0.05). Lamb survival was increased by 7 lambs p er 100 ewes exposed to rams in both years. (Year 1 at weaning, NS; Yea r 2 at tail docking, P < 0.001). It was concluded that the strategy im proved both lamb survival and lamb performance possibly due to an effe ct of lupin supplementation on colostrum and subsequent milk productio n. (C) 1998 Elsevier Science B.V. All rights reserved.